S78 Diffuse Large B Cell Lymphoma of the Anal Transition Zone After Ileal Pouch Anal Anastomosis: A Report of 4 Cases

Abstract

Background: Development of lymphoma at the anal transition zone (ATZ) following restorative proctocolectomy with ileal pouch anal anastomosis (IPAA) is extremely rare, with less than 10 cases described in the literature. Methods: We retrospectively analyzed our prospectively collected database on pelvic pouches. Patients who developed lymphoma at the ATZ were included in this study, and oncological and functional outcomes were described. Results: Out of 5,070 patients undergoing IPAA between 1983 and 2021, 4 developed lymphoma of the ATZ (3 males, 1 female). The histology was diffuse large B cell lymphoma (DLBCL) in all cases. All patients had a diagnosis of ulcerative colitis, with concomitant primary sclerosing cholangitis (PSC) in 2 cases. The indication to IPAA was colon cancer in 2 cases, dysplasia in one case, and fulminant colitis in one case. Three patients had a J pouch, while one had an S pouch. The median interval between IPAA and lymphoma development was 7 years (range 3-12). Two patients had a previous history of hematologic malignancies (acute myeloid leukemia and nodal marginal zone lymphoma, respectively), while one was immunosuppressed due to liver transplantion for PSC. In 3 cases, the ATZ was the first site involved, while one case first presented as a thyroid lymphoma, achieved remission with R-CHOP, and later developed a recurrence at the ATZ. Three patients had stage IAE DLBCL at presentation, while one patient had stage IV disease. In all cases, the presenting symptoms were akin to pouchitis, with no patient exhibiting B symptoms. Two patients had concomitant acute kidney injury due to lymphoma-related obstructive uropathy with bilateral hydronephrosis requiring bilateral nephrostomies. All patients received R-CHOP as first line treatment, with all patients with stage IAE disease achieving remission. The patient with stage IV DLBCL was one of the 2 patients with obstructive uropathy: he was diverted with loop ileostomy and died of lymphoma-related sepsis 3 months after lymphoma development. Similarly, the other patient with obstructive uropathy developed a recurrence shortly after remission and died of lymphoma-related sepsis 10 months after lymphoma development. Regarding the other 2 patients, the post-transplant patient developed recurrence 3 years after remission: immunosuppression was stopped, and she went into remission one month later. She had no further recurrences, and died 4 years later due to progressive multifocal leukoencepalopathy with her pouch still intact. The last patient, who had no predisposing factors for lymphoma development, had no recurrence; he is still alive with no evidence of disease and his pouch intact 7.5 year after lymphoma development. Conclusion(s): Diffuse large B cell lymphoma of the ATZ is a rare occurrence that can be effectively treated with chemotherapy without resulting in pouch failure. Although uncommon, lymphoma should be considered in the differential in patients with symptoms of pouchitis and predisposing factors or a history of hematologic malignancies.